1. Field of the Invention
The present invention relates generally to a bone examination apparatus and method, and more particularly, to a bone examination apparatus and method for examining the bone density of femur and the loosening status of hip joint.
2. Description of the Prior Art
Bone is an important organ of human body. It can support our body, protects other organs, performs hematopoiesis, and adjusts minerals. However, with the ever-increasing pressure in hectic modern life, people nowadays take unbalanced nutrients and lack enough exercises, thus their bone quality is descended. Moreover, the bone density of human beings approaches the peak at about 30 years of age, and flows away by about 0.3 to 2% every year. Therefore, regular examination to find, prevent and treat related problems such as osteoporosis, bone necrosis, or joint degeneration, as early as possible has been the key point of health examination.
To reach the goal of bone density examination, a number of equipment and methods have been developed, such as X-ray examination, single photon absorptiometry (SPA), dual photon absorptiometry (DPA), computed tomography (CT), dual energy X-ray absorptiometry (DEXA), and ultrasonic examination.
X-ray examination can only be applied to detect bone with calcium or fracture lower than 70%, so it is not sensitive and accurate enough. SPA or DPA apply the photon released by isotope to detect bone density. Because of the problem of half-life and stability, it is unusual to use SPA or DPA in examination. Moreover, although both the sensitivity and the accuracy of CT are very high, the irradiation and cost for examination make it hard to use CT for bone examination.
With the advantages of short examining time, no irradiation, and low cost, ultrasonic examination has been widely applied to examine bone density. For example, Taiwan patent publication no. 144806 discloses a method and apparatus for ultrasonic analysis of bone density in vivo, and Taiwan patent publication no. 492859 discloses an apparatus and method for ultrasonic bone assessment. However, ultrasonic examination can be easily effected by skin, muscle, or other soft tissues, so as to affect the accuracy of the examination.
Additionally, because of the advantages of low irradiation and small error, Dual-energy X-ray Absorptiometry (DEXA) has been the major equipment for bone density examination. However, DEXA needs a longer examination duration, and the volume of the equipment is giant, both limit the portability and popularity of it.
Therefore, it is necessary to develop a bone density examination equipment with certain accuracy, safety, and convenience.